The present invention generally relates to seat belt retraction mechanisms.
Seat belts and retractors are commonly used as part of a safety restraint system to protect vehicle occupants. A typical retractor includes a spool, a frame for supporting the spool, a locking mechanism(s) to stop the spool from rotating and web and/or vehicle sensors for initiating spool lockup upon sensing certain dynamic criteria.
A practical seat belt retractor should of course be of low cost and of high quality. The underlying design must be flexible to accommodate varying customer performance criteria. Such criteria will generally include, in addition to the above: small package size to permit the retractor to be easily fit into virtually any location and any orientation within a vehicle, and light weight construction. In addition, the retractor should be relatively easy to manufacture and have a design amenable to automated manufacturing techniques. The retractor should be characterized by low belt extraction and retraction forces and an overall quiet operation. The retractor should be capable of using one or more sensors such as a web sensor and vehicle sensor without a major change in the basic structure of the retractor and be smooth in its operation and not jam, as well as be capable of withstanding loading forces in the range of 18 KN.
It is the object of the present invention to provide an improved seat belt retractor.
Accordingly, the invention comprises: a seat belt retractor comprising: a frame having a base and two parallel side walls extending therefrom. The retractor additionally includes a spool, rotatably positioned relative to the side walls. A support frame or skeleton is provided for the spool enabling same to be fabricated of less costly, lightweight, non-structural material. The support frame, as opposed to the spool, effectively absorbs the forces developed during operation. The support frame or skeleton comprises first and second disks joined by a plurality of bars or pins. The first and second disks are positioned on opposite sides of the spool and the pins extend through the spool such as through cooperating bores in the spool. A shaft, of defined shape is received in a complementary shaped opening in each disk to rotationally link the disks together and also to provide an axis of rotation of the spool and disks.
In the preferred embodiment of the invention, the frame is stepped, kinked or bent defining a shoulder therein. A dual acting pawl locking mechanism is supported upon the frame sides and movable into engagement with teeth formed on the disks. The frame is designed to facilitate drop-in insertion of the locking mechanism. The locking mechanism is moved into locking engagement upon activation of one or more sensing mechanisms such as a vehicle and web sensor.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.